The heaviest foam US composites has is 16 lb. I read on their web site that for optimum expansion of the foam, the temperature should be warm. They mentioned 80 degrees.I don't think i'll be able to get the garage or basement that warm! Any comments on temperature affecting your application?
thank you both for the pouring tips.
Yes, it was definitely the 16lb foam then.
And yes, it was definitely not 80 degrees. I did try to keep it warmish, maybe it was 70 degrees, dunno. The foam develops quite a bit of heat by itself.
I would not sweat
the temperature but of course you wouldn't want to do it in a freezing unheated space either. The stuff has a high heat storage capacity, so even if the space where you do the pouring is not super-warm, if you keep it in a nice cosy room and only bring it out for the pour you should be fine.
Oh, one more tip, this one is important: Go to Home Depot, buy a paint stirrer for your power drill. You have about a minute time to mix each batch, no way you can do this with a wooden paddle or something. I got the one with the plastic vanes; after the foam had hardened on them, you can get it off easily and think about the next batch.
I did at least 10 batches for the rudder. You don't want to pour too much at once for two reasons: one is that the stuff hardens before it fills the volume, and two, because it develops a lot of heat. And there is no harm to have lots of batches (other than that it takes a bit more time): This stuff adheres WONDERFULLY to itself. As well as to anything else